Gulpfile: add tasks `clear` and `learnsets`
Gulpfile: add tasks `clear` and `learnsets`

- 'gulp clear' removes everything currently cached.
- `gulp learnsets` is intended to check /**/learnsets.js files for proper packing. This is no longer done in `npm test`.

xCrystal/Pokemon-Showdown,Kevinxzllz/PS-Openshift-Server,Pokemon-Devs/Pokemon-Showdown,CharizardtheFireMage/Showdown-Boilerplate,EmmaKitty/Pokemon-Showdown,AbsolitoSweep/Absol-server,Zipzapadam/Server,Sora-League/Sora,AWailOfATail/awoat,Wando94/Spite,svivian/Pokemon-Showdown,SolarisFox/Pokemon-Showdown,Enigami/Pokemon-Showdown,TheManwithskills/DS,PS-Spectral/Spectral,TheManwithskills/New-boiler-test,Hidden-Mia/Roleplay-PS,Kokonoe-san/Glacia-PS,hayleysworld/serenity,DB898/theregalias,forbiddennightmare/Pokemon-Showdown-1,SkyeTheFemaleSylveon/Pokemon-Showdown,ZestOfLife/PSserver,Wando94/Spite,NoahVSGamingYT/Pokemon-Showdown,Lauc1an/Perulink-Showdown,Pikachuun/Pokemon-Showdown,gustavo515/batata,yashagl/pokemon-showdown,BuzzyOG/Pokemon-Showdown,danpantry/Pokemon-Showdown,DesoGit/Tsunami_PS,Articuno-I/Pokemon-Showdown,SkyeTheFemaleSylveon/Pokemon-Showdown,Sora-League/Sora,BlazingAura/Showdown-Boilerplate,zek7rom/SpacialGaze,lFernanl/Zero-Pokemon-Showdown,Firestatics/Firestatics46,KewlStatics/Alliance,JennyPRO/Jenny,Alpha-Devs/OmegaRuby-Server,Firestatics/Omega-Alpha,Alpha-Devs/Alpha-Server,forbiddennightmare/Pokemon-Showdown-1,urkerab/Pokemon-Showdown,TheManwithskills/COC,lFernanl/Zero-Pokemon-Showdown,Zipzapadam/Server,AustinXII/Pokemon-Showdown,Ecuacion/Pokemon-Showdown,PauLucario/LQP-Server-Showdown,sama2/Dropp-Pokemon-Showdown,ZestOfLife/FestiveLife,kuroscafe/Showdown-Boilerplate,Sora-League/Sora,JellalTheMage/PS-,Kevinxzllz/PS-Openshift-Server,AWailOfATail/Pokemon-Showdown,ScottehMax/Pokemon-Showdown,Lauc1an/Perulink-Showdown,Sora-Server/Sora,TheFenderStory/Pokemon-Showdown,lAlejandro22/lolipoop,Git-Worm/City-PS,kotarou3/Krister-Pokemon-Showdown,SilverTactic/Showdown-Boilerplate,hayleysworld/serenityserver,Guernouille/Pokemon-Showdown,lFernanl/Lumen-Pokemon-Showdown,Mystifi/Exiled,sama2/Lumen-Pokemon-Showdown,panpawn/Pokemon-Showdown,zek7rom/SpacialGaze,Vacate/Pokemon-Showdown,SSJGVegito007/Vegito-s-Server,Flareninja/Lumen-Pokemon-Showdown,DarkSuicune/Kakuja-2.0,Wando94/Pokemon-Showdown,Ridukuo/Test,Enigami/Pokemon-Showdown,Flareninja/Showdown-Boilerplate,Bryan-0/Pokemon-Showdown,jd4564/Pokemon-Showdown,MasterFloat/LQP-Server-Showdown,SolarisFox/Pokemon-Showdown,Irraquated/Showdown-Boilerplate,ankailou/Pokemon-Showdown,PrimalGallade45/Lumen-Pokemon-Showdown,arkanox/MistShowdown,bai2/Dropp,abrulochp/Dropp-Pokemon-Showdown,ZeroParadox/BlastBurners,anubhabsen/Pokemon-Showdown,piiiikachuuu/Pokemon-Showdown,abrulochp/Lumen-Pokemon-Showdown,KewlStatics/Shit,Zarel/Pokemon-Showdown,lFernanl/Pokemon-Showdown,PrimalGallade45/Dropp-Pokemon-Showdown,DesoGit/Tsunami_PS,megaslowbro1/Showdown-Server-again,TbirdClanWish/Pokemon-Showdown,Pikachuun/Pokemon-Showdown-SMCMDM,hayleysworld/Showdown-Boilerplate,TheManwithskills/Dusk--Showdown,QuiteQuiet/Pokemon-Showdown,Mystifi/Exiled,abulechu/Lumen-Pokemon-Showdown,Pokemon-Devs/Pokemon-Showdown,Volcos/SpacialGaze,sama2/Dropp-Pokemon-Showdown,bai2/Dropp,zczd/enculer,TheManwithskills/COC,SSJGVegito007/Vegito-s-Server,PrimalGallade45/Lumen-Pokemon-Showdown,gustavo515/test,anubhabsen/Pokemon-Showdown,HoeenCoder/SpacialGaze,Syurra/Pokemon-Showdown,gustavo515/final,aakashrajput/Pokemon-Showdown,lFernanl/Pokemon-Showdown,JennyPRO/Jenny,DesoGit/TsunamiPS,AWailOfATail/Pokemon-Showdown,QuiteQuiet/Pokemon-Showdown,KewlStatics/Showdown-Template,ankailou/Pokemon-Showdown,SilverTactic/Showdown-Boilerplate,TheManwithskills/Creature-phil-boiler,EmmaKitty/Pokemon-Showdown,TheManwithskills/Dusk--Showdown,yashagl/yash-showdown,AustinXII/Pokemon-Showdown,ShowdownHelper/Saffron,megaslowbro1/Pokemon-Showdown,KewlStatics/Shit,kuroscafe/Showdown-Boilerplate,Nineage/Origin,DarkSuicune/Pokemon-Showdown,azum4roll/Pokemon-Showdown,Hidden-Mia/Roleplay-PS,ehk12/clone,ShowdownHelper/Saffron,ZeroParadox/ugh,gustavo515/gashoro,Enigami/Pokemon-Showdown,Sora-Server/Sora,Alpha-Devs/Alpha-Server,Pikachuun/Pokemon-Showdown-SMCMDM,KaitoV4X/Showdown,PS-Spectral/Spectral,panpawn/Pokemon-Showdown,Alpha-Devs/OmegaRuby-Server,Flareninja/Pokemon-Showdown,RustServer/Pokemon-Showdown,svivian/Pokemon-Showdown,Nineage/Origin,hayleysworld/Showdown-Boilerplate,AbsolitoSweep/Absol-server,superman8900/Pokemon-Showdown,TheManwithskills/Creature-phil-boiler,TheManwithskills/serenity,Pikachuun/Pokemon-Showdown,aakashrajput/Pokemon-Showdown,KewlStatics/Alliance,Lord-Haji/SpacialGaze,BlazingAura/Showdown-Boilerplate,xfix/Pokemon-Showdown,JellalTheMage/Jellals-Server,Celecitia/Plux-Pokemon-Showdown,urkerab/Pokemon-Showdown,yashagl/yash-showdown,svivian/Pokemon-Showdown,Firestatics/Firestatics46,Firestatics/omega,svivian/Pokemon-Showdown,PauLucario/LQP-Server-Showdown,Irraquated/Pokemon-Showdown,theodelhay/test,megaslowbro1/Pokemon-Showdown,Elveman/RPCShowdownServer,DB898/theregalias,danpantry/Pokemon-Showdown,kupochu/Pokemon-Showdown,kuroscafe/Paradox,Vacate/Pokemon-Showdown,hayleysworld/serenity,xfix/Pokemon-Showdown,NoahVSGamingYT/Pokemon-Showdown,gustavo515/test,theodelhay/test,abulechu/Dropp-Pokemon-Showdown,brettjbush/Pokemon-Showdown,ehk12/bigbangtempclone,kotarou3/Krister-Pokemon-Showdown,Celecitia/Plux-Pokemon-Showdown,javi501/Lumen-Pokemon-Showdown,brettjbush/Pokemon-Showdown,Articuno-I/Pokemon-Showdown,Lord-Haji/SpacialGaze,RustServer/Pokemon-Showdown,Irraquated/Pokemon-Showdown,jd4564/Pokemon-Showdown,PrimalGallade45/Dropp-Pokemon-Showdown,megaslowbro1/Pokemon-Showdown-Server-for-megaslowbro1,JellalTheMage/PS-,BuzzyOG/Pokemon-Showdown,abulechu/Lumen-Pokemon-Showdown,Wando94/Pokemon-Showdown,TheManwithskills/New-boiler-test,Irraquated/Pokemon-Showdown,SilverTactic/Dragotica-Pokemon-Showdown,jumbowhales/Pokemon-Showdown,k3naan/Pokemon-Showdown,arkanox/MistShowdown,Zarel/Pokemon-Showdown,BuzzyOG/Pokemon-Showdown,Pablo000/aaa,DarkSuicune/Pokemon-Showdown,gustavo515/final,TheManwithskills/Server,xCrystal/Pokemon-Showdown,MeliodasBH/boarhat,CreaturePhil/Showdown-Boilerplate,ScottehMax/Pokemon-Showdown,xCrystal/Pokemon-Showdown,Pablo000/aaa,scotchkorean27/Pokemon-Showdown,HoeenCoder/SpacialGaze,MayukhKundu/Flame-Savior,KewlStatics/Showdown-Template,ShowdownHelper/Saffron,TheDiabolicGift/Lumen-Pokemon-Showdown,JellalTheMage/Jellals-Server,SilverTactic/Dragotica-Pokemon-Showdown,AWailOfATail/Pokemon-Showdown,abrulochp/Lumen-Pokemon-Showdown,HoeenCoder/SpacialGaze,svivian/Pokemon-Showdown,TheManwithskills/Server---Thermal,Zarel/Pokemon-Showdown,EienSeiryuu/Pokemon-Showdown,Bryan-0/Pokemon-Showdown,scotchkorean27/Pokemon-Showdown,abulechu/Dropp-Pokemon-Showdown,psnsVGC/Wish-Server,piiiikachuuu/Pokemon-Showdown,psnsVGC/Wish-Server,zczd/enculer,hayleysworld/serenityc9,Mystifi/Exiled,TheDiabolicGift/Lumen-Pokemon-Showdown,panpawn/Gold-Server,AnaRitaTorres/Pokemon-Showdown,cadaeic/Pokemon-Showdown,TheFenderStory/Showdown-Boilerplate,HoeenCoder/SpacialGaze,QuiteQuiet/Pokemon-Showdown,TheDiabolicGift/Showdown-Boilerplate,TheManwithskills/DS,ehk12/coregit,megaslowbro1/Pokemon-Showdown-Server-for-megaslowbro1,superman8900/Pokemon-Showdown,Elveman/RPCShowdownServer,TheFenderStory/Pokemon-Showdown,Flareninja/Pokemon-Showdown,azum4roll/Pokemon-Showdown,Ecuacion/Pokemon-Showdown,panpawn/Gold-Server,Syurra/Pokemon-Showdown,Lord-Haji/SpacialGaze,ehk12/clone,Flareninja/Lumen-Pokemon-Showdown,panpawn/Gold-Server,AnaRitaTorres/Pokemon-Showdown,lFernanl/Lumen-Pokemon-Showdown,PS-Spectral/Spectral,ZeroParadox/ugh,Enigami/Pokemon-Showdown,sirDonovan/Pokemon-Showdown,hayleysworld/serenityc9,EienSeiryuu/Pokemon-Showdown,yashagl/pokemon-showdown,TheManwithskills/serenity,Volcos/SpacialGaze,aakashrajput/Pokemon-Showdown,Git-Worm/City-PS,xfix/Pokemon-Showdown,kupochu/Pokemon-Showdown,megaslowbro1/Showdown-Server-again,xfix/Pokemon-Showdown,k3naan/Pokemon-Showdown,hayleysworld/serenityserver,Neosweiss/Pokemon-Showdown,ZestOfLife/FestiveLife,DarkSuicune/Kakuja-2.0,MeliodasBH/boarhat,DesoGit/Tsunami_PS,cadaeic/Pokemon-Showdown,TheManwithskills/Server---Thermal,ehk12/bigbangtempclone,TheManwithskills/Server,Ecuacion/Lumen-Pokemon-Showdown,Flareninja/Showdown-Boilerplate,lAlejandro22/lolipoop,Ecuacion/Lumen-Pokemon-Showdown,KewlStatics/Pokeindia-Codes,TheFenderStory/Showdown-Boilerplate,Firestatics/Omega-Alpha,MeliodasBH/Articuno-Land,Neosweiss/Pokemon-Showdown,AustinXII/Pokemon-Showdown,MayukhKundu/Flame-Savior,gustavo515/gashoro,urkerab/Pokemon-Showdown,abrulochp/Dropp-Pokemon-Showdown,sama2/Lumen-Pokemon-Showdown,jumbowhales/Pokemon-Showdown,Kokonoe-san/Glacia-PS,TbirdClanWish/Pokemon-Showdown,gustavo515/batata,KewlStatics/Pokeindia-Codes,MeliodasBH/Articuno-Land,AWailOfATail/awoat,TheDiabolicGift/Showdown-Boilerplate,Irraquated/Showdown-Boilerplate,ehk12/coregit,MasterFloat/LQP-Server-Showdown,CreaturePhil/Showdown-Boilerplate,Sora-Server/Sora,kuroscafe/Paradox,CharizardtheFireMage/Showdown-Boilerplate,DesoGit/TsunamiPS,ZestOfLife/PSserver,ZeroParadox/BlastBurners,jumbowhales/Pokemon-Showdown,xfix/Pokemon-Showdown,javi501/Lumen-Pokemon-Showdown,Firestatics/omega,sirDonovan/Pokemon-Showdown,sirDonovan/Pokemon-Showdown,Guernouille/Pokemon-Showdown,KaitoV4X/Showdown,Ridukuo/Test,CreaturePhil/Showdown-Boilerplate